Abrasive detergent compositions



added to the abrasive materials.

, 2,945,815 ABRASIVE DETERGENT COMPOSITIONS Ramon Bruno Diaz, DouglasManor, 'N.Y., assignor to Un t S a s, Pawfl fQ Colgate-PalmoliveCompany,New York, N.Y., a corw poration of Delaware No Drawing. Filed Jan. 2,1957, Ser. No. 632,025

7 6 Claims. (Cl. 252- 138) This invention relates to new improvedabrasive detergent compositions. More particularly it relates toabrasive detergent powders containing, as their essential Iconstituents, a major proportion of silica powder of particular particlesize range and a minor proportion of a synthetic detergent.

I were ground and used directly as scouring powders.

Later, inorganic salts, inorganic detergents and soaps were In recentyears synthetic detergents have supplanted soaps in some of theseproducts.

For household use and in other applications too, it is often eitherhighly desirable or even essential that the cleanser should possessexcellent cleaning power while still being extremely mild to thesubstratum, which may be almost any material but most often is eitherporcelain, aluminum, copper, stainless steel, or glass. Sometimesscouring cleansers are also used on painted and enameled materials,linoleums, plastics, and other easily marrable surfaces. A cleansercomprising an abrasive that seriously'scratches these surfaces willdestroy their beauty.

' Even if one application does no apparent harm to the surface, repeateduse will eventually cause an objectionabledulling or loss of surfacelusterJ Most of the pres- I cut commercial scouring cleansers meet witha high degree of consumer acceptance but nevertheless, comparative testsof consumer. preference indicate a strong prior choice for the milderpowders if all other characteristics 4 -are maintained equal.

* Iu an' attempt to make scouring cleansers and similar preparationsthat areinot too harsh for industrial and consumer acceptance','fvarious techniques of manufacture have :been employed and many othershave been suggested. .These processes have usually been restricted tocontrol of the abrasive ingredients since scratching by jthe othercomponents of a scouring powder ordinarily is negligible. r V It hasbeen suggested that the abrasive should be of a softer material such ascrushed limestone, preferably of harder .abrasive materials to preventdeep scratching.

In some instances the material has been reduced to below 10 microns. Inother cases, the maximumpa'rticle size limit has been set at levelsranging from 60 mesh through 400 mesh and down to below 2 microns. v r

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Sometimes the abradant has been coated with an alkali metal silicatewhile in other products the abrasive action has been cushioned byincorporation of materials such as bentonite, cellulose derivatives andwater soluble salts of smaller particle size. I

The use of the processes listed above either does not result over-all ina sufiiciently improved scouring cleanser or is inherently too costly tobe supported by this highly competitive low priced product. Removal ofthe larger abrasive particles alone does not produce an acceptablescouring cleanser of excellent cleaning power.

In accordance with the present invention, there is provided a preferredabrasive detergent composition of reduced scratching properties whilestill being a good cleaner, which composition consists essentially of amajor proportion of silica having a particle size range between about 14microns and the maximum which will allow the silica to pass a 200 meshsieve, and a minor proportion, up to about 20%, of a water solublesynthetic organic detergent.

- Silica is the abrasive ingredient of the invented com- Of thematerials suggested in the art for this requisite scouring ability, sizereduction processing and classification characteristics,non-hygroscopicity, color and density, as Well as ready availability, inquantity and at low cost. Usually it is obtained from clean sand,

the colorless type being especially favored for use in householdcleansers. While quartz is the most common crystalline form of silica,the other crystalline and -95% and preferably from -95% by Weight on a'dry basisr The silica particles are most preferably within the 14.micron to 200 mesh range because, when. of that size, -the.abrasivedetergent powders made therefrom are surprisingly excellent cleanersacting to polish rather than to scratch scoured surfaces. When theabrasive particles -are between 6 microns and mesh the'scouring powdersare still mild polishing agents but are not as good in cleaning as arethe 14 micron-200 mesh products.

The other essential ingredient of the abrasive deter- ,gent powders is asynthetic organic detergent. Soaps are not considered to be syntheticorganic detergents. They are not desirable as detergents in the presentcompositions. because of their reaction with metal ions in hard water toform insoluble soaps which do not easily rinse oif the surfaces to becleaned.

, M The synthetic organic detergents that are used in the presentcompositions may be either anionic, cationic or nonionic or compatiblemixtures thereof. Usually they should be solids but liquid materialsfind use where they can be absorbed on a component of the composition byprocedures known to the art.

Among the anionic detergents contemplated as within the invention, arethe sulfated and sulfonated synthetic detergents, especially thosehaving about 12 to 26 carbon atoms in the molecule. Of the lattersuitable sulfated and sulfonated detersive compounds it is preferred toemploy the alkyl aromatic sulfonates and aliphatic sulfatesandsulfonates of about 12 to 22 carbon atoms.

Patented July 19, 1 9;6O

the alkyl group is from 10-18, preferably l2-16 carbon atoms and wherethe alkyl group is obtained by polymerizing propylene or butyleneaccording to methods known in the trade.

Other suitable detergents are sulfated and sulfonated aliphaticcompounds having alkyl groups of 12 to 22 carbon atoms. Within thisgroup are the sulfuric acid esters of polyhydric alcohols incompletelyesterified by higher fatty acids, e.g., coconut oil monoglyceridemonosulfate, tallow diglyceride monosulfate; the long chain alcoholsulfates, e.g., lauryl sulfate, cetyl sulfate; the higher fatty acidesters of a sulfonic acid, e.g., oleic acid ester of isethionic acid;the fatty acid alkylolamide sulfates; the fatty acid amides of aminoalkyl 'sulfonic acids, e.g., lauric acid amide of taurine and the like.As examples of the cationic detergents may be noted the long chain alkylquaternary ammonium salts, e.g., cetyl pyridinium chloride. The cationicdetergents will usually be compounded with a nonionic detergent. Amongnonionic compounds it is preferred to employ block copolymers ofethylene oxide and propylene oxide, such as those of the formulaHO(EtO),,(PrO) (EtO) H, Whose molecular weight is 1000 to 2000 andwherein the ethylene oxide constitutes from 20-90% by weight. Such amaterial is sold under the trade name Pluronic F-68.

Specific examples of anionic, cationic and nonionic detergents have beenlisted above but detergents other than those listed are alsocontemplated providing only that they are of satisfactory detersiveability. It will be noted that the synthetic detergents listed are allof the foaming type. This is so because these detergents are preferred,it having been established that the foamv generated coacts with thesilica, helping to lift off and float away grease or other soiling agentwhile at the same time aiding in keeping the silica particles in motion.The motion of the silica results in a continually new presentation ofscouring surfaces to the film to be removed and also preventscementitious action of the very small particles on the larger, bettercleaning sizes and consequent insulation of the better cleaners from theundersirable film. In some applications, it may be desirable to employnonfoaming detergents, or detergents may be usedin conjunction withother compounds which limit their foaming, e.g., with silicones forcoating scoured surfaces.

Because of the various physical properties of the many syntheticdetergents the amount of synthetic detergent should be adjusted in eachformula for maximum effectiveness. Generally, the least amount ofdetergent that will give a good cleaning effect is the right amount touse. Some satisfactory compositions can be made with as little as 0.5%synthetic organic detergent although most' often 2% or more is used.Almost always less than 10% synthetic organic detergent will be employedalthough in some instances as much as about 20% may be found desirableto efiect superior cleaning. Above 20% organic detergent content, thecharacter of the abrasive cleaning composition undergoes an undersirablechange. It tends to become less free flowing, to cake in the package andto rinse poorly.

Other adjuvants may complement the essential abrasive detergentcomposition. Foam-enhancing additives such as lauric myristicdiethanolarnide may be employed. Inorganic salts, particularlypolyphosphates such as sodium tripolyphosphate, tetrasodiumpyrophosphate and sodium hexametaphosphate may be used because of theirown detergenecy or synergistic effect on detergency of the essentialanionic synthetic detergent. Anti-corrosion additives, e.g., sodiumsilica of Na O/SiO ratio about 2.3, and anti-caking agents such asmagnesium trisilicate or bentonite find use, as do gumsandsoil-suspending agents such as carboxymethyl cellulose. Chemicalagents for removing oxide films, e.g., organic acids, are desirablecomponents of cleaning and polishing compositions such as copperbrighteners. Bleaching agents of the oxygenating type, e.g., sodiumperborate, or of the chlorinating type, e.g., trichlorocyanuric acid,may be incorporated in cleansers because of their sanitizing ability andpower to remove stains. Of course, perfumes are usually desirable foraesthetic reasons. For the most part the present compositions will bemanufactured in dry .powder form but, when desirable, suspensions,pastes or gels in aqueous or non-aqueous media may also be made.

As has already been indicated, the silica abrasive, which constitutes amajor proportion of the present abrasive detergent composition, is mostpreferably of particle size range from 14 microns to 200 mesh. In thescience of particle size measurement, there are various diameters'andother measurements or calculated factors used to describe particles andtheir size distribution. In'sieving it is a combination of sieve openingand breadth of a particle that is controlling. In measuring particlesize microscopically, it is usual to record the minor dimension (whichcorresponds to breadth because particles tend to lie fiat on themicroscope slide, the thickness not being visible to the viewer). Indetermining particle size by sedimentation methods, the diameter ofanequivalent spherical particle is calculated.

It is clear that particles can differ greatly in shape and still havethe same breadths, minor dimensions or equivalent spherical diameters.As a practical matter, however, the smaller or sub-sieve size silicaparticles powdered for use in the present scouring cleansers are, forthe greater part, of a shape approaching the spheroidal, being manyfaceted polyhedrons and not needles or plates. Results obtained byapplying Stokes law to sedimentation data show that the diameter ofan'equivalent sphere is close to the minor diameter of such a sub-sievesize particle as viewed through a microscope. Particles larger than'325' mesh are not as regular as those of sub-sieve size and usually theminor diameters (microscopic) or breadths of such particles are slightlylarger than the side of the sieve opening. For instance silica; passinga 200 mesh sieve will have 'a maximum particle size of about 88 micronswhile that passing a 140 mesh sieve will be, at most, about 125 microns.Sedimentation data to which Stokes law has been applied establish thatthe. largest particles through a 200 mesh standard sieve are of -84microns equivalent spherical diameter while those passing a 140 meshsieve are of -120 microns. equivalent spherical diameten. In

this specification the upper particle size limit is set relative tosieve size and the lower limits correspond to microscopically determinedbreadthv or equivalent spherical diameter.

The silica particles in the 14 micron to 200 mesh range are those thatwill pass a 200 mesh sieve and which have had removed by a sedimentationmethod the particles -it has been held to under 2%.

about 1410 50: microns after which itfia-ttens perceptibly. A typicalclassified silica of this invented composition contains about 50% byweight over 34 microns and about 30% over 44 microns. The silica tobeclassified may initially contain particles in the 0 to 250 microns rangeobtained from sand by the usual ball mill, hammer mill,

.or other equivalent size reduction techniques. This silica should beatleast 50% by weight below 200 mesh. Particles over 200 mesh areusually removed by mechanical sifting through a US. Bureau of Standards.screen. Par- .ticles under. 14 microns may be removed bysedimentationtechniques, e.g-., by air separation. In air separation, centrifugalforce causes heavier particles in a moving an" ,medium to be thrown tothe outside of a circular. path more rapidly than smaller particles- Byusing special throttles the lighter or heavier (smaller orela-rger)particles can b e removed. It is not necessary to perform 'completeseparations in single operations and inmany 'cases it'will be desirableto separate part of the material 'rather accurately and recycle thebalance.

Any other apparatus or method of classification may be used providingthat the character of classification. is the same.

In the. above discussion, certain limits on silica particle sizes havebeen set but due to thenature of the classification and "analyticalmethods, it is not practicable precise- -ly to separate or analyzeparticles according to size.

No matter how carefully and exactly a separation'is made, when dealingwith silica flours there will always be present a considerable number ofoversized .or undersized particles due to the inherent difficulty .offractionation and the limitations of equipment and expense ofprocessing. At best a rather sharply'defined'separation can result. t l

The upper size limit on silica can be fairly accurately obtained byscreening but someoversize particles'will unavoidably be present,usually less than,5%, when sedimentation methods are used to removecoarser particles.

More difiiculty is encountered in eliminating the under- .sizeparticles. In good practice the proportion of undersizesfines will beless than and in someinstances However, even if the limitations of theequipment prevent more than 60-70% removal of undersize (leaving up tobelow specifi-' cation size) the product obtained will still be of use.

Despite the fact that it is well recognized in the art that oversize andundersize particles are usually-present, it-is customary to describeparticle size limitations in absolute terms, it beingunderstood thatsuch boundary figures are reader to know in which range most of theparticles lie. In this specification the reported ranges are thoserepre-.

sentative of the silica tested, unrepresentative or accidental particlesbeing omitted. H'Iheaccuracy of themicror.-.

scopic analysis is usually within about 10% In the above discussion ofsize distribution, for the sake of simplicity, a single preferred silexof lA- rnierons to 200 mesh was mentioned but it is clear thatmuch of vthat explanation'also applies to' a similar compositionim I: sieve andair separation until it icontaine'd particles within the range of 14microns (breadth dimension) to 200 mesh.

Other classifications were made to yield silicasof 6 mithe 6 micron to140 mesh range.

The particle size of the synthetic org' jnic detergent and othernon-abrasive adjuvants used is not critical because these m-aterialsjarepresent in minor amountsjand do not contribute appreciably to theabrading or scratching power of the present compositions. The particlesof synthetic detergent, adjuvant, or synthetic detergent combined withadjuvants should be smallenough so as not to create a heterogeneity;apparent to the eye or sense of'touch and objectionable, or suflicientto cause stratification. Usually these granules or heads will be lessthan 200 inicrons.

To make the di sclosed compositions, it is possible merely tomechanically mix the classified silica with dried synthetic organicdetergent. Initially, the synthetic detergent may be mixed with some orall of the other adjuvant materials. In one process it is first crutchedwith builders and then spray dried. The resulting builtdetergent is thenwell mixed with the silica; if desired, the mixture may be homogenizedby passage through a subsequent mixing or size-reduction apparatus,providing that such treatment does not subdivide the silica so much asto make it too fine for the present compositions.

The invented abrasive detergent compositions are far superior to theusual scouring powders. When compared to a' typical commerciallysuccessful scouring powder the present composition was found to excel incleaning and it did not scratch test surfaces as the other cleanser haddone.

When scouring powders, identical except for silica particle size, weremade, those comprising a silica in the range 14 micron to 200 mesh wereclearly much milder in scratching action than most other powders tested.Surprisingly, they were also better in cleaning power-than scouringpowders made from silex of a larger average particle size.

These results are very important because good cleaningand scouringpowder without objectionable abrasion are the prime requisites of asuperior scouring powder. No reason is known for the unexpectedlysuperior'cleaning power of the 14 micron to 200 mesh product butageneral theory explains the salutary eifect of removing the coarser andfiner silica particles. 7

Removal of the coarse particles is desirable because, being larger, theymake deeper pits when pressed against surfaces to be cleaned. They alsotendto. slide, rather than roll, and thereby generate long scratchesinstead of the less noticeable pits. Although the coarser particles areremoved the medium particles left are still good cleaners. "Theyfunction mechanically to dislodge soil from substrata, being abrasive tothe soil but not the surface underneath. However, the removal ofcoarsematerial increases the proportion of fines and, when slurried in aliquid these fines are then sufiicientin number to fill the intersticesand form a relatively immobile dispersion in which the medium particlesare surrounded by smaller ones. The extreme fines are too small to begood cleaners (they cannot sufficiently abrade the soil) and themoderatelysized particles are insulated by them. Thus, the removal ofthe fines enables medium particles to clean satisfactorily, and withoutscratching. In evaluating the invented products cleaning power wastested by removing completely a baked grease mixture from a vitreoussurface. This test simulated cleaning of a'n oven, range orgrease-coated sink. Scratching and pitting were checked by examinationof microphotographs and by a' machine for detecting surfaceirregularities as'small as a millionth of an inch. i

The following examples are given to illustrate the invention. All.amountsand percentages in the specification and claims are by weightunless otherwise indicated.

. EXAMPLES A commercial silica (quartz) flour wasclassified by crons to200 mesh, 6 microns to mesh: and 14 microns to 140 mesh. The accuracy ofseparationwas, such that only about 4% of the particles in any cut wereoutside the range and the distributionlwas .aboutlequal between theoversize and undersize;

The commercial silica was size analyzed by passing 7 through us. Bureauof Standards sieves with the following results:

Table 1 Size Range, Parts Microns (by (screen weight) dimension) Through60 on 80 Mesh- 259-177 0. 2 Through 80 on 100 Mesh- 1.1-149 n. 4 Through100 on 120 Mesh 149-125 0. 9 Through 120 on 140 Mesh. l2o105 2.1 Through1 40 on 170 Mesh" 105-88 3. 4 Through 170 on 200 Mesh- 8844 4. 7 Through200 on 230 Mesh- 74-02 5. 3 Through 230 on 270 Mesh. 02. 53 5. Through270 on 325 Mesh. 53-44 7. 1 Through 325 mesh 44-0 :0. 4 Total 100. 00

The sub-sieve size material was separated into additional fractions byDietert Micro Particle Classifier and also by a standard sedimentationmethod. Particles were measured (minor axis) microscopically with thefollowing result:

From the classified silica, various silex mixtures were made. Some ofthese are compared to the original silex in Table III following.

The silexes of Table III were each made into an abrasive detergentpowder of the formula:

Made by pulverizing a detergent composition obtained by spray drying toabout 8% moisture a slurry of approximate dry analysis 35 parts sodiumdodecyl benzene sulfonate (the alkyl group being propylene tetramer), 40parts sodium tripolyphosphate, 7 parts sodium silicate (NazO/Si02=2.35)and 8.3 parts sodium sulfate.

The above scouring powders were comparatively tested for scratchiness,cleaning efiiciency, rinsability, foaming, flowability, and density.

The tendency to scratch was compared by a mechanically reproduciblemethod simulating actual use. In this test glass plates were rubbed withvarious scouring powders in slurry form. The test was run in triplicateand twelve readings were taken on each plate of the deepest scratches orpittings on the plate. The average depth of these 36 readings wasapproximately 20% greater for sample B than for sample A. Sample E alsopitted to a greater depth than B, but most important of all, samples Aand B caused no unsightly long scratches while sample B made many. Whentest glasses scoured with difierent scouring cleansers were viewed undera microscope, that to which sample B had been applied show severalwell-defined scratches passing all the way across a 2 millimeter fieldbut sample B gave only traces of very short faint scratches and sample Acaused no scratches at all. Samples A and B also pitted noticeably lessthan sample E.

In a test of cleaning power porcelain squares were coated with a layerof hydrogenated vegetable fat mixed with linseed oil and were then bakedin an oven at 280 F. for 22 minutes. After cooling, a mechanical arm,equipped with a stroke counter, was used to rub a slurry of scouringcleanser against the coated plates. The number of strokes required tocompletely remove the bakedon grease was recorded. Three tests of eachpowder were Table [II Parts by Weight and Weight Percent in Size RangeComposition Designator A B D E Size Range, microns (Screen dimension )ormicroscopic measurement. t; at 3-: 17M 019 0: 9 2.1 2. 1 3.4 3.8 3.4 5.13.4 3.4 4.7 5.3 4.7 7.0 4.7 4.7 9.0 5.3 6.0 5.3 v 6.5 5.3 7.9 5.3 5.3 9.4 5. 5 6.2 5. 5 6.8 5. 5 8.2 5. 5 5. 5 12.1 7. 1 8.0 7. 1 8. 8 7. 1 10.67. 1 7. 1 14. 8 8. 7 9.8 8.7 10. 7 8. 7 13.0 8. 7 8.7 24. 8 14.6 16. 414. 6 18. 1 14. 6 21. 8 14. 6 14. 6 29. 9 17. 6 19. 8 17. 6 21. 7 17.626. 4 17.6 17. 6 22.1 24. 7 22.1 27. 4 22.1 22. 1 7. 4 7. 4

Table IV Cleaning Inefiicieney Composition Deslgnator Silica ParticleSize Sgokes ver Control 14 microns-200 mesh. 1 6 micrnsl40 mesh 11 6microns200 mesh 14 D. 14 micronsl40 mesh. 17 E eontroL. 0250 microns l 0F 0 microns200 mesh 47 G 0 microns-140 mesh 38 H control 0-250 microns 10 1 About 140 strokes needed to clean perfectly.

scratchiness) increased with particle size but in the present case the Dcleanser contains more coarse particles and nevertheless the micron-200mesh composition is superior. Likewise the 6 micron-140 mesh powder isbetter than the D cleanser. And, of course, both the A and B powders aregreatly superior to the F and G compositions. Thus, a non-scratchingscouring powder has been made which is of cleaning efiiciency equal tothat of a commercially successful coarser cleanser.

Composition A rinses oil a surface more readily than do B, C, or D whichmeans less effort will be required by the user to remove traces of thepowder from the cleaned surface. Composition A also compares favorablywith B, C, D and the controls in other important properties, such asfoaming power, density and freedom of flow.

The above invention has been described in conjunction with illustrativeexamples. It will be obvious to those skilled in the art that variationsand modifications can be made without departing from the principlesdisclosed or going outside the scope of the invention or purview of theclaims.

What is claimed is:

1. An abrasive detergent composition which is substantiallynon-scratching to porcelain and is of excellent cleaning power, whichconsists essentially of a major proportion of silica, the particle sizesof which are distributed throughout the range from about 6 microns tothe maxi- Y mum size which will pass a 140 mesh sieve, the weightdistribution of the silica particles being that obtained bysize-reducing sand so that a major proportion of the sand subjected tosize reduction will pass a 200 mesh sieve and then removing particlesoutside the 6 micron to 140 mesh sieve range, and a minor proportion, upto about 20%, of a water soluble synthetic organic detergent.

2. An abrasive detergent composition which is substantiallynon-scratching to porcelain and is of excellent cleaning power, whichconsists essentially of a major proportion of silica, the particle sizesof which are distributed throughout the range from about 14 microns tothe maximum size which will pass a 200 mesh sieve, the weightdistribution of the silica particles being that obtained bysize-reducing sand so that a major proportion of the sand subjected tosize reduction will pass a 200 mesh sieve and then removing particlesoutside the 14 micron to 200 mesh sieve range, and a minor proportion,up to about 20%, of a water soluble synthetic organic detergent.

3. An abrasive detergent composition according to claim 2 in which thewater soluble synthetic organic detergent is a member of the classconsisting of sulfated and sulfonated water soluble foaming syntheticorganic detergents.

4. An abrasive detergent composition according to claim 3 in which thewater soluble synthetic organic detergent is present in a minorproportion, up to about 10%, and the composition also includes a minorproportion, up to about 10%, of water soluble phosphate.

5. A scouring cleanser which is substantially non scratching toporcelain and is of excellent cleaning power, which consists essentiallyof a major proportion of silica, the particle sizes of which aredistributed throughout the range from about 14 microns to the maximumsize which will pass a 200 mesh sieve, the weight distribution of silicaparticles being that obtained by size-reducing sand so that a majorproportion of the sand subjected to size reduction will pass a 200 meshsieve and then removing the particles outside the 14 to 200 mesh sieverange, a minor proportion, up to 10% of sodium alkyl benzene sulfonatein which the alkyl group is a propylene polymer of 12 to 15 carbon atomsand a minor proportion,

. up to 10%, of sodium tripolyphosphate.

6. A scouring cleanser which is substantially nonscratching to porcelainand is of excellent cleaning power, which consists essentially of and ofsilica, the particle sizes of which are distributed throughout the rangefrom about 14 microns to the maximum size which will pass a 200 meshsieve, the weight distribution of the silica particles being such thatabout 50% thereof are over 34 microns and about 30% are over 44 microns,this weight distribution of the silica particles being that obtained bysize-reducing sand so that a major proportion of the sand subjected tosize reduction will pass a 200 mesh sieve and then removing particlessmaller than 14 microns by air separation and removing any particleswhich will not pass a 200 mesh sieve by screening, 0.5 to 10% of sodiumalkyl benzene sulfonate in which the alkyl group is a propylene polymerof 12 to 15 carbon atoms and a minor proportion, up to 10%, of sodiumtripolyphosphate.

References Cited in the file of this patent UNITED STATES PATENTS2,428,317 Moran Sept. 30, 1947 2,739,129 Manchot Mar. 30, 1956 FOREIGNPATENTS 284,367 Great Britain Jan. 23, 1928 732,791 Great Britain June29, 1955 1,063,900 France Dec. 23, 1953 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No, 2,945 a15 y 11 1960 Ramon BrunoDiaz It is hereby certified that error appears in the-printedspecification of the above "numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 1, line 55 for "ingredients" read ingredient column 4, line 5 for"silica" read silicate column 6,, line 30, for "powder" read powercolumn 7, Table I under the heading "Size Ranze, Microns (screendimensiony' eighth item for "62.53" read 62-53 column 9,, line 17 for"15 micron" read 14 micron- "=8 Signed and sealed this 11th day of April1961s.

(SEAL) Attest:

ERNEST W SWIDER ARTHUR W. CROCKER Attesting Officer A ti g Commissionerof Patents

1. AN ABRASIVE DETERGENT COMPOSITION WHICH IS SUBSTANTIALLYNON-SCRATCHING TO PROCELAIN AND IS OF EXCELLENT CLEANING POWER, WHICHCONSISTS ESSENTIALLY OF A MAJOR PROPORTION OF SILICA, THE PARTICLESSIZES OF WHICH ARE DISTRIBUTED THROUGHOUT THE RANGE FROM ABOUT 6 MICRONSTO THE MAXIMUM SIZE WHICH WILL PASS A 140 MESH SIEVE, THE WEIGHTDISTRIBUTION OF THE SILICA PARTICLES BEING THAT OBTAINED BYSIZE-REDUCING SAND SO THAT A MAJOR PROPORTION OF THE SAND SUBJECTED TOSIZE REDUCTION WILL PASS A 200 MESH SIEVE AND THEN REMOVING PARTICLESOUTSIDE THE 6 MICRON TO 140 MESH SIEVE RANGE, AND MINOR PROPORTION, UPTO ABOUT 20%, OF A WATER SOLUBLE SYNTHETIC ORGANIC DETERGENT.